1. Field of the Invention
The present invention relates to a device for transmitting electrical currents, including a slip ring unit and a printed circuit board, as well as to its employment in connection with remote-controlled objects.
2. Discussion of Related Art
Slip rings are employed in many technical fields for transmitting electrical signals or electrical power from a stationary electrical unit to a rotating electrical unit. For example, slip rings are employed for the operation of remote-controlled cameras. In this application, electrical signals must be transmitted from the pivotable camera to an electronic evaluating device, and further than that also the electrical power and signals for operating of drive mechanisms, for example for zoom regulation or an electrical drive mechanism for pivoting. In the same way, electrical slip rings are used in connection with other electrical devices, for example rotatable searchlights, laser installations or robotic components.
A slip ring structure is shown in U.S. Pat. No. 3,042,998, the entire contents of which is incorporated herein by reference. In U.S. Pat. No. 3,042,998 the wires of the slip ring rotor are conducted in grooves extending in the axial direction and whose spacing in the circumferential direction has an even graduation. Because of this guidance, the wires project out of the slip ring along the rotor circumference in an orderly manner and with even spacing. No reference is made in this document to the use of a printed circuit board.
U.S. Pat. No. 5,213,374 discloses a slip ring arrangement in which a printed circuit board has been placed inside the housing of the actual slip ring unit. This printed circuit board is essentially used for signal amplification inside the slip ring unit. The internal printed circuit board of this patent disclosure cannot transmit a torque, because an appropriate housing has been provided there for this function. Moreover, no ordered guidance in the sense of a functionally-related local assignment of the connecting wires to the printed circuit board is provided in U.S. Pat. No. 5,213,374, the entire contents of which is incorporated herein by reference.
A wireless slip ring is disclosed in U.S. Pat. No. 4,870,311, the entire contents of which is incorporated herein by reference. In U.S. Pat. No. 4,870,311 strip conductors on printed circuit boards are used in place of the wires in the slip ring unit. The printed circuit boards, all of which are located inside the slip ring unit in accordance with this patent, are connected as flexible cables, which assure the connection with external devices. A flange is provided, which is fastened on the rotating body and is used for an appropriate introduction of a torque.
The above-described known devices have the disadvantage that the torque required for the relative movement between the rotor and the stator is supplied via separate mechanical devices which must be provided in addition to the already present printed circuit boards. In particular, in connection with slip ring units which are produced in large numbers, it is necessary to achieve a material-saving construction, which moreover requires the fewest number of components.
Further details of the present invention ensue from the following description of an exemplary embodiment by the attached drawings.